K2: add a black box test to confirm KT-53718 now works properly (JVM IR only)

Related to: KT-57584, KT-58110

compiler/testData/codegen/box/extensionClasses/noRedeclaration.kt

@@ -0,0 +1,34 @@
+// TARGET_BACKEND: JVM_IR
+// Does not pass on other backends for various reasons, e.g.
+// - FIR/WASM: IR declaration with signature "/x|{}x[0]" found in SymbolTable and not found in declaration storage
+// - IR/JS: IrPropertyPublicSymbolImpl for /x|{}x[0] is already bound: PROPERTY name:x visibility:public modality:FINAL [val]
+// - Old BE: Couldn't inline method call: with(A()) { ... }
+// - See also: KT-57584, KT-58110
+// LANGUAGE: +ContextReceivers
+// ISSUE: KT-53718
+
+class A
+
+context(A)
+val x: Int
+    get() = 1
+
+val x: Int
+    get() = 2
+
+context(A)
+fun foo() = 3
+
+fun foo() = 4
+
+fun box(): String {
+    if (x != 2) return "x = $x"
+    if (foo() != 4) return "foo() = ${foo()}"
+
+    with(A()) {
+        if (x != 1) return "context x = $x"
+        if (foo() != 3) return "context foo() = ${foo()}"
+    }
+
+    return "OK"
+}